全文获取类型
收费全文 | 554054篇 |
免费 | 5932篇 |
国内免费 | 1653篇 |
专业分类
化学 | 294435篇 |
晶体学 | 8532篇 |
力学 | 24256篇 |
综合类 | 16篇 |
数学 | 66251篇 |
物理学 | 168149篇 |
出版年
2021年 | 4555篇 |
2020年 | 5145篇 |
2019年 | 5565篇 |
2018年 | 7112篇 |
2017年 | 7092篇 |
2016年 | 10916篇 |
2015年 | 6864篇 |
2014年 | 10608篇 |
2013年 | 25560篇 |
2012年 | 19481篇 |
2011年 | 23812篇 |
2010年 | 16922篇 |
2009年 | 16704篇 |
2008年 | 22010篇 |
2007年 | 21758篇 |
2006年 | 20312篇 |
2005年 | 18198篇 |
2004年 | 16824篇 |
2003年 | 14929篇 |
2002年 | 14655篇 |
2001年 | 16669篇 |
2000年 | 12598篇 |
1999年 | 9853篇 |
1998年 | 8209篇 |
1997年 | 7952篇 |
1996年 | 7682篇 |
1995年 | 6952篇 |
1994年 | 6851篇 |
1993年 | 6584篇 |
1992年 | 7422篇 |
1991年 | 7399篇 |
1990年 | 7167篇 |
1989年 | 6923篇 |
1988年 | 6932篇 |
1987年 | 6838篇 |
1986年 | 6421篇 |
1985年 | 8418篇 |
1984年 | 8580篇 |
1983年 | 7090篇 |
1982年 | 7187篇 |
1981年 | 7036篇 |
1980年 | 6619篇 |
1979年 | 7163篇 |
1978年 | 7309篇 |
1977年 | 7143篇 |
1976年 | 7090篇 |
1975年 | 6667篇 |
1974年 | 6622篇 |
1973年 | 6789篇 |
1972年 | 4710篇 |
排序方式: 共有10000条查询结果,搜索用时 21 毫秒
921.
922.
923.
I. M. Yusopova B. Tashkhodzhaev A. S. Narzullaev S. S. Sabirov B. T. Ibragimov 《Chemistry of Natural Compounds》1990,26(2):230-231
Institute of the Chemistry of Plant Substances, Uzbek SSR Academy of Sciences, Tashkent. Abu Ali ibn Sina [Avicenna] Tashkent State Medical Institute, Dushanbe. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 279–281, March–April, 1990. 相似文献
924.
S. V. Lev R. P. Zakirova Z. Saatov M. V. Gorovits N. K. Abubakirov 《Chemistry of Natural Compounds》1990,26(1):40-41
The possibility has been studied of obtaining ecdysteroids — ecdysterone and turkesterone — with the aid of a culture of the tissues and cells of the plantAjuga turkestanica. Conditions have been selected under which the yield of ecdysteroids in the culture of tissues and cells is comparable with amounts of the same substances in the organs of the whole plant.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 51–52, January–February, 1990. 相似文献
925.
M. O. Lozinskii Yu. A. Fialkov V. S. Khomenko T. A. Pavich 《Theoretical and Experimental Chemistry》1990,26(2):228-231
A series of new adducts of fluorinated REE -diketonates with triphenylphosphine oxide was synthesized. The paths of their fragmentation under electron impact were investigated. It was shown that in contrast to the complex with 1,1,1,2,2,3,3-heptafluoro-7,7-dimethyloctane-4,6-dione, the complexes of europium with 1-trifluoromethoxy-1,1-difluoro-5,5-dimethylhexane-2,4-dione and 1, 1,1-trifluoro-5,5-dimethylhexane-2,4-dione form dimeric associates in the gaseous phase. The reasons for this difference in the behavior of the complexes and the possible structure of one of the dimers are discussed.Translated from Teoreticheskaya i Eksperimental'naya Khimiya, Vol. 26, No. 2, March–April, 1990. 相似文献
926.
927.
V. A. Vinokurov Yu. N. Polivin M. A. Silin E. A. Ageev M. A. Zatikyan R. A. Karakhanov 《Russian Chemical Bulletin》1989,38(9):1984-1984
Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2154–2155, September, 1989. 相似文献
928.
U. Kreibig K. Fauth M. Quinten D. Schönauer 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1989,12(1-4):505-514
First, some general remarks concerning macroscopic “cluster matter” are given. In the second part, three recent, mainly optically and electron-microscopically performed investigations are discussed which deal with special properties of noble metal cluster systems forming the building units of this kind of matter:(1) dressed Au-55 clusters,(2) electromagnetic coupling effects among coagulated clusters,(3) the transition towards compact inhomogeneous matter caused by coalescence of clusters. 相似文献
929.
930.
Mössbauer study of iron reduction in hematite containing mineral originated from Aswan area in Egypt
E. Kuzmann N. Eissa B. Molnár A. Vértes 《Journal of Radioanalytical and Nuclear Chemistry》1988,127(3):169-176
Mössbauer spectroscopy was used to study iron reduction in mineral originated from Aswan area in Egypt. The Mössbauer spectra of samples heat treated at 1000 °C in hydrogen atmosphere show a gradually reduction process of hematite. The main phase of sample aged for 1 h is magnetite, while alpha-iron as well as some silicates and wustite type oxide can be detected in sample aged for 3 h. Further aging of sample results in dissolution of alloying elements /Si, Al/, being present in the samples. This process starts already in samples aged at 1000 °C for 4 h, but it is more expressive in minerals heat treated at 1200 °C or 1300 °C, when all paramagnetic phases disappeared. 相似文献